/*
* Copyright (C) 2015 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "swscale_internal.h"
int ff_sws_alphablendaway(SwsContext *c, const uint8_t *src[],
int srcStride[], int srcSliceY, int srcSliceH,
uint8_t *dst[], int dstStride[])
{
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(c->srcFormat);
int nb_components = desc->nb_components;
int plane, x, y;
int plane_count = isGray(c->srcFormat) ? 1 : 3;
int sixteen_bits = desc->comp[0].depth_minus1 >= 8;
unsigned off = 1<<desc->comp[0].depth_minus1;
unsigned shift = desc->comp[0].depth_minus1 + 1;
unsigned max = (1<<shift) - 1;
int target_table[2][3];
for (plane = 0; plane < plane_count; plane++) {
int a = 0, b = 0;
if (c->alphablend == SWS_ALPHA_BLEND_CHECKERBOARD) {
a = (1<<desc->comp[0].depth_minus1)/2;
b = 3*(1<<desc->comp[0].depth_minus1)/2;
}
target_table[0][plane] = plane && !(desc->flags & AV_PIX_FMT_FLAG_RGB) ? 1<<desc->comp[0].depth_minus1 : a;
target_table[1][plane] = plane && !(desc->flags & AV_PIX_FMT_FLAG_RGB) ? 1<<desc->comp[0].depth_minus1 : b;
}
av_assert0(plane_count == nb_components - 1);
if (desc->flags & AV_PIX_FMT_FLAG_PLANAR) {
for (plane = 0; plane < plane_count; plane++) {
int w = plane ? c->chrSrcW : c->srcW;
int x_subsample = plane ? desc->log2_chroma_w: 0;
int y_subsample = plane ? desc->log2_chroma_h: 0;
for (y = srcSliceY >> y_subsample; y < FF_CEIL_RSHIFT(srcSliceH, y_subsample); y++) {
if (x_subsample || y_subsample) {
int alpha;
unsigned u;
if (sixteen_bits) {
ptrdiff_t alpha_step = srcStride[plane_count] >> 1;
const uint16_t *s = (const uint16_t *)(src[plane ] + srcStride[plane ] * y);
const uint16_t *a = (const uint16_t *)(src[plane_count] + (srcStride[plane_count] * y << y_subsample));
uint16_t *d = ( uint16_t *)(dst[plane ] + dstStride[plane ] * y);
if ((!isBE(c->srcFormat)) == !HAVE_BIGENDIAN) {
for (x = 0; x < w; x++) {
if (y_subsample) {
alpha = (a[2*x] + a[2*x + 1] + 2 +
a[2*x + alpha_step] + a[2*x + alpha_step + 1]) >> 2;
} else
alpha = (a[2*x] + a[2*x + 1]) >> 1;
u = s[x]*alpha + target_table[((x^y)>>5)&1][plane]*(max-alpha) + off;
d[x] = av_clip((u + (u >> shift)) >> shift, 0, max);
}
} else {
for (x = 0; x < w; x++) {
if (y_subsample) {
alpha = (av_bswap16(a[2*x]) + av_bswap16(a[2*x + 1]) + 2 +
av_bswap16(a[2*x + alpha_step]) + av_bswap16(a[2*x + alpha_step + 1])) >> 2;
} else
alpha = (av_bswap16(a[2*x]) + av_bswap16(a[2*x + 1])) >> 1;
u = av_bswap16(s[x])*alpha + target_table[((x^y)>>5)&1][plane]*(max-alpha) + off;
d[x] = av_clip((u + (u >> shift)) >> shift, 0, max);
}
}
} else {
ptrdiff_t alpha_step = srcStride[plane_count];
const uint8_t *s = src[plane ] + srcStride[plane] * y;
const uint8_t *a = src[plane_count] + (srcStride[plane_count] * y << y_subsample);
uint8_t *d = dst[plane ] + dstStride[plane] * y;
for (x = 0; x < w; x++) {
if (y_subsample) {
alpha = (a[2*x] + a[2*x + 1] + 2 +
a[2*x + alpha_step] + a[2*x + alpha_step + 1]) >> 2;
} else
alpha = (a[2*x] + a[2*x + 1]) >> 1;
u = s[x]*alpha + target_table[((x^y)>>5)&1][plane]*(255-alpha) + 128;
d[x] = (257*u) >> 16;
}
}
} else {
if (sixteen_bits) {
const uint16_t *s = (const uint16_t *)(src[plane ] + srcStride[plane ] * y);
const uint16_t *a = (const uint16_t *)(src[plane_count] + srcStride[plane_count] * y);
uint16_t *d = ( uint16_t *)(dst[plane ] + dstStride[plane ] * y);
if ((!isBE(c->srcFormat)) == !HAVE_BIGENDIAN) {
for (x = 0; x < w; x++) {
unsigned u = s[x]*a[x] + target_table[((x^y)>>5)&1][plane]*(max-a[x]) + off;
d[x] = av_clip((u + (u >> shift)) >> shift, 0, max);
}
} else {
for (x = 0; x < w; x++) {
unsigned aswap =av_bswap16(a[x]);
unsigned u = av_bswap16(s[x])*aswap + target_table[((x^y)>>5)&1][plane]*(max-aswap) + off;
d[x] = av_clip((u + (u >> shift)) >> shift, 0, max);
}
}
} else {
const uint8_t *s = src[plane ] + srcStride[plane] * y;
const uint8_t *a = src[plane_count] + srcStride[plane_count] * y;
uint8_t *d = dst[plane ] + dstStride[plane] * y;
for (x = 0; x < w; x++) {
unsigned u = s[x]*a[x] + target_table[((x^y)>>5)&1][plane]*(255-a[x]) + 128;
d[x] = (257*u) >> 16;
}
}
}
}
}
} else {
int alpha_pos = desc->comp[plane_count].offset_plus1 - 1;
int w = c->srcW;
for (y = srcSliceY; y < srcSliceH; y++) {
if (sixteen_bits) {
const uint16_t *s = (const uint16_t *)(src[0] + srcStride[0] * y + 2*!alpha_pos);
const uint16_t *a = (const uint16_t *)(src[0] + srcStride[0] * y + alpha_pos);
uint16_t *d = ( uint16_t *)(dst[0] + dstStride[0] * y);
if ((!isBE(c->srcFormat)) == !HAVE_BIGENDIAN) {
for (x = 0; x < w; x++) {
for (plane = 0; plane < plane_count; plane++) {
int x_index = (plane_count + 1) * x;
unsigned u = s[x_index + plane]*a[x_index] + target_table[((x^y)>>5)&1][plane]*(max-a[x_index]) + off;
d[plane_count*x + plane] = av_clip((u + (u >> shift)) >> shift, 0, max);
}
}
} else {
for (x = 0; x < w; x++) {
for (plane = 0; plane < plane_count; plane++) {
int x_index = (plane_count + 1) * x;
unsigned aswap =av_bswap16(a[x_index]);
unsigned u = av_bswap16(s[x_index + plane])*aswap + target_table[((x^y)>>5)&1][plane]*(max-aswap) + off;
d[plane_count*x + plane] = av_clip((u + (u >> shift)) >> shift, 0, max);
}
}
}
} else {
const uint8_t *s = src[0] + srcStride[0] * y + !alpha_pos;
const uint8_t *a = src[0] + srcStride[0] * y + alpha_pos;
uint8_t *d = dst[0] + dstStride[0] * y;
for (x = 0; x < w; x++) {
for (plane = 0; plane < plane_count; plane++) {
int x_index = (plane_count + 1) * x;
unsigned u = s[x_index + plane]*a[x_index] + target_table[((x^y)>>5)&1][plane]*(255-a[x_index]) + 128;
d[plane_count*x + plane] = (257*u) >> 16;
}
}
}
}
}
return 0;
}